ESDA2010-24782 EXPERIMENTAL STUDY OF CORRUGATED TUBES UNDER LATERAL LOADING

ABSTRACT The protection of structures under impact loading often necessitates the need for energy absorbers; devices designed to absorb the impact energy in a controlled manner and hence, protect the structure under consideration. Thinwalled tubes are widely used as energy absorbers in various vehicles and moving parts. The objective of the present study is to investigate the energy absorption characteristic of tubes with corrugations in different geometries, in lateral direction. In order to produce corrugations, an innovative solution is introduced. Corrugations can be very easily generated on the surface of cylindrical aluminum tubes by stamping method. Corrugations with different wavelengths and amplitudes can be produced by this method. Experimental tests are conducted to study the effect of changing corrugation geometry (type and amplitude). Quasi-static tests are carried out whose results for lateral compression show that tubes with corrugation have a higher mean crushing force and this force is directly proportional to number of corrugations and their amplitude. Moreover, it is observed that corrugated tubes can absorb approximately four times more energy than tubes without corrugations, in the same size and weight. Finally, considering the experimental tests, corrugated tubes are shown to be more effective in lateral direction as an energy absorber, and they also exhibit desirable force-deflection responses which are important in the design of energy absorbing devices

Interactions between Entomopathogenic Fungus, Metarhizium Anisopliae and Sublethal Doses of Spinosad for Control of House Fly, Musca Domestica

Background: Metarhizium anisopliae strain IRAN 437C is one of the most virulent fungal isolates against house fly, Musca domestica. The objective of this study was to determine the interaction of this isolate with sublethal doses of spino­sad against housefly.Methods: In adult bioassay, conidia of entomopathogenic fungus were applied as inoculated bait at 105 and 107 spore per gram and spinosad at 0.5, 1 and 1.5 µg (A.I.) per gram bait. In larval bioassay, conidia were applied as combina­tion of spore with larval bedding at 106 and 108 spore per gram and spinosad at sublethals of 0.002, 0.004 and 0.006 µg (AI) per gram medium. Results: Adult mortality was 48% and 72% for fungus alone but ranged from 66–87% and 89–95% in combination treat­ments of 105 and 107 spore/g with sublethal doses of spinosad respectively. The interaction between 105 spore/g with sublethals exhibited synergistic effect, but in combination of 107 spore in spite of higher mortality, the interac­tion was additive. There was significant difference in LT50 among various treatments. LT50 values in all combination treat­ments were smaller than LT50 values in alone ones. Larval mortality was 36% and 69% for fungus alone but ranged from 58%–78% and 81%–100% in combination treatments of 106 and 108 spore/g medium with sublethals of spino­sad respectively. The interaction was synergistic in all combination treatments of larvae.Conclusion: The interaction between M. anispliae and spinosad indicated a synergetic effect that increased the house fly mortality as well as reduced the lethal time

Etiologic Agents of Otomycosis in the North-Western Area of Iran

BACKGROUND: Otomycosis is a superficial fungal infection often involves the pinna and external auditory canal. It is a pathologic condition, with Candida and Aspergillus, the most common fungal species. It is common worldwide but more prevalent in tropical and subtropical countries. OBJECTIVES: The aim of this study was to determine the etiologic agents and local epidemiologic pattern of otomycosis in northwest Iran. PATIENTS AND METHODS: A series of 140 patients with clinically symptomatic otomycosis were studied in 21 cities, towns, and villages throughout northwest Iran between 2009 and 2011. Clinical samples were collected by swabs and then assessed by mycological investigation. RESULTS: Otomycosis was diagnosed in 129 cases (92%, 76 male, 53 female) with the highest prevalence of cases occurring in males between 21 - 40 years of age. From an etiological point of view, 116 patients (90%, 21 - 40 years old) were infected by saprophytic mold and 9 patients (7%) were infected by yeast. Three cases (2%) involved dermatophytes, and in one case (1%) the subject was infected with Eurotium (the perfect stage of Aspergillus fumigatus). Aspergillus niger was the most common mold that was isolated, followed by A. flavus, A. fumigatus, Penicillium spp., Fusarium spp., and Rhizopus spp. A total of 2 yeasts belonging to genus Candida, C. albicans and C. tropicalis, were isolated. CONCLUSIONS: Our study showed a high prevalence of otomycosis in the northwestern area of Iran. As such, proper diagnosis and treatment by aseptic techniques for this disease is urgently needed